Changes of the oceanic circulation in the North Atlantic and the Arctic during the last 2000 years

Van Meerbeeck, C. (2005). Changes of the oceanic circulation in the North Atlantic and the Arctic during the last 2000 years. MSc Thesis. Université Catholique de Louvain; Département de Physique; Institut d'Astronomie et de Géophysiques /MareLac: Gent. 31 + bijlagen pp.

the North Atlantic Ocean and surrounding has been the setting for numerous oceanografic studies during the course of the history of scientific knowledge. A relatively recent development has put a major impetus on the advance of research in Atmospheric & Oceanic Sciences, namely the use of General Circulation Models - GCMs - capable of realistically reproducing atmospheric and oceanic circulation physical processes acting upon the climate system or interactions between internal processes. In this study, we assess the variability of the oceanic circulation of the North Atlantic and Arctic regions, by comparing reconstructions available from recent research with model results of 25 simulations on a forced coupled atmosphere-sea ice-ocean GCM of intermediary complexivity, ECBLIT-CLIO. In general, forced variability was well reproduced by the model in a qualitative way, but due to a 3°by3° horizontal grid size and the inability to reproduce internal variability, underestimation of the amplitude of the noted variability unabled us to draw any solid conclusions on basis of model results alone, notwithstanding often providing additional clues to hypotheses. At most sites, the warming during the Industrial Period of the 19th and 20th centuries was unprecedented. One more warm phase, the Medieval Warm Period, coincided with generally weakened thermohaline circulation, whereas the cold Little Ice Age saw an increase.